The drug barons consider him a pirate and a thief. Yusuf Hamied, a Cambridge-educated multi-millionaire who lives for the summer months in what used to be Lady Shirley Porter's London apartment, believes he is doing Ghandi's bidding. He manufactures perfect copies of many of the world's best and most important medicines and sells them at a snip. Dr Hamied and his family are certainly very rich but many poor people owe him their health, without which they would be destitute indeed.

The question of Dr Hamied's motivation is absorbing but at the end of the day irrelevant. What matters is that he exists. He single-handedly broke the cartel of the big drug companies by offering to supply Aids drugs at less than a tenth of their prices. That audacious offer at a big European Commission meeting on Aids in September 2000 ("you could hear the breath being sucked out of the room" said Bill Haddad, former New York Post investigative journalist turned US generics boss) made everything possible.

The assumption that Aids drugs were not for the poor - that they could not afford them and therefore that there was no point even thinking about ways to get people treated - was blown out of the water.

Now, in the post-Hamied era, the genie will not go back in the bottle. The big drug companies have been forced to drop their prices for these new and powerful drugs and offer them to a market they had no interest in developing - the impoverished African states where a whole generation of parents, teachers and workers are dying.

Dr Hamied's prices are still lower - his Bombay-based company, Cipla, offers a three drug cocktail for around $304 per year which used to sell for around $12,000 and would now cost $727 from the brand-name companies.

And yet his sales are few in countries where the need is desperate. Fewer than 50,000 people are being treated out of nearly 30 million infected with the lethal HIV virus in Africa, and - although Malawi is buying them - most of those are not getting Cipla's drugs.

Part of the reason is money - $304 is still impossible in countries with a per capita income of under $200 a year. But another part of it is a fight-back by the US and Europe based big-name pharmaceutical industry, which has long wanted to wipe the buccaneering generics companies off the face of the planet. Their long-term strategy to do that, through a World Trade Organisation agreement called Trips (trade related intellectual property rights) - which will sign up every nation to protect patents on new drugs for 20 years - is now in jeopardy because of the Aids crisis and Cipla's affordable medicines.

The drug giants have dropped their prices and argue that there is no need for generic piracy. But many of those who are concerned about the damage being wreaked on the economies of poor nations by a single virus have come to believe that it is not safe for the world to rely on voluntary price reductions by generous drug barons for desperately needed medicines to keep poor people alive and nations stable.

Campaigners in the US and Europe, as well as governments in developing countries, now see generics - or the threat of them - as the only way to get affordable medicines for all sorts of diseases that afflict the population of poor countries and damage their economies.

Just over a year ago, they secured an exemption clause to Trips, called the Doha Declaration, which allows developing countries to ignore patents and buy generics in a health crisis. Now the fight is on to decide in which countries and for which diseases poor people should be allowed cheap medicines - the US government, which champions the industry, wants to rule out such illnesses as asthma, diabetes and cancer and restrict the concession to the very poorest nations.

The crucial issue is whether the generics companies of India, Brazil and Thailand will be allowed to export to countries that cannot make their own cheap copies after the Trips patent rules bite in 2005. Unless they can, new drugs invented for Aids or other diseases will be untouchable and unaffordable in Africa for 20 years.

Cipla was set up as an Indian solution to India's health problems by Dr Hamied's father in 1935 when war stopped medicines arriving from Europe. Its website features a picture of Ghandi expressing his delight at visiting "this Indian enterprise".

In 1972, India passed a law which permitted medicines to be copied even if they were under international patent, as long as the process was not the same. There are now hundreds of generic companies in India - many of them tiny. Cipla is one of the biggest, with a market capitalisation, said Dr Hamied, of about $1.4bn.

"I don't want to make money on Aids drugs," he says. "I make enough money on other things. On this particular issue, can't we all pool our resources? I make 800 drugs. If I don't make money on six, why should I worry?"

Dr Hamied runs a free cancer hospital in India. There are reasons to believe in his altruism. "I'm not going to take it with me, so I have to leave it here," he says. But there's no doubt he stands to win all ways round.

His public stand has given Cipla excellent publicity. The World Health Organisation has endorsed the quality of his generic Aids drugs and approved his factories. And the fight over the Trips agreement could bring him a lot more business not only from the poorest countries but - and this is why the research-based companies are fighting so hard - also the massive developing markets of China and South America.

Dr Hamied, though, is frustrated. He is disappointed with the governments of Aids-hit nations, who are not placing orders for his drugs. "It is a joke," he says. "I should have the demand. Demand creates the incentive to produce, but with only 50,000 in the whole of Africa, where is the demand?" If demand grew as fast as the spread of the virus, he could not keep pace.

He would like see countries set up their own generics factories, and he has offered to show them how produce Aids drugs for free. The Global Fund should put up the money, he says. None of this happening.

Cipla sells a three-drug cocktail in one pill, called Triomune, to be taken twice day, which makes treatment much easier in poor countries. Malawi buys it for the couple thousand patients who can afford to pay $28 month, but its $196m from the Global Fund will only buy treatment for 50,000 more.

Dr Hamied will shortly launch the world's first once-a-day, three-drug treatment, called Odivir. It's clearly well suited to poor countries and it will be affordable, he says, but there's reason to suppose it will be taken up where other drugs have not been.

"India has four million cases and I'm breaking my head to make my government take a more active role," he says. "I offered totally free nevirapine (to prevent babies being infected by their mothers birth) and nobody takes it. It is up to the various governments to avail [themselves] of the opportunities offered. What has really saddened me is, firstly, the governments and, secondly, I have been totally disillusioned by the UN who talk, talk, talk and do nothing at all."

What, apart from lack of money in the poorest, is stopping the governments biting Cipla's hand off? The research-based pharmaceutical industry would say the political will is not there. But patents have been an issue. In Ghana, for instance, says Dr Hamied, it was GlaxoSmithKline that challenged the decision to import generic versions of drugs which were under patent there.

But there are countries where Aids drugs not patented. According to Bill Haddad, who has voluntarily taken up Cipla's cause in the US, "the governments are too scared of the government to buy generics". The US trade representative bats for the giant pharmaceutical companies. Whatever the WTO trade rules say about allowing countries to buy generics a health crisis, he suggests, there are those would rather not risk the wrath and possible sanctions of the US.